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10th Jan 2021

Here’s why you should ignore your BMI this January – and always

Melissa Carton

January is typically the month we all start looking at our fitness.

Every year (with the expectation of this year due to lockdown) gym memberships go up in January.

Usually it’s because we’ve all been getting into the Roses at Christmas and want to get back into shape, sometimes it’s because it’s your New Year’s resolution.

Nevertheless fitness, weight loss and diet are always some of the most searched topics come the start of the year but not all the information out there is helpful.

For instance, it’s time that we chuck BMI (Body Mass Index) right in the bin.

The body mass index (BMI) is a measure that uses your height and weight to work out if your weight is healthy. The BMI calculation divides an adult’s weight in kilograms by their height in metres squared. For example, A BMI of 25 means 25kg/m2.

The problem with this is that BMI does not take into account muscle mass, bone density and overall body composition leading to some very inaccurate results for many people.

Over Christmas I received a smart watch and while setting up the fitness tracker it asked for my BMI. I used the BMI calculator on the NHS website (there didn’t seem to be a HSE one) and these were my results.

Keep in mind that before you see these that I’m a UK size 12 in trousers and skirts and anywhere between a UK 8-10 in tops and blouses.

Yes, according to BMI I am obese. Not just a little overweight, obese.Why is that? Because the only factors it’s taking into account is the fact that I weigh 70kg.

Does it take into account the weight of my breasts which are 34DD? No. Does it take into account that I have muscular legs and arms and that muscle weighs more than fat? No.

In fact, BMI takes into account very little which is why many schools of medicine and medical journals have discredited how useful it actually is.

Still, because it is so well known and used by a lot of fitness apps, BMI is a go to for many people starting out on their fitness journey. If it is to stay around, it really needs to be updated with more factors taken into account.

But to be honest, I think in 2021 it needs to go. It’s an inaccurate measure of health and after 2020, we’ve all been through enough – we don’t need the body shaming on top of it.

If you do check you BMI and it tells you that you’re overweight or obese, please take into account everything above before you start thinking about losing weight.

This year, eat a well balanced diet, do some exercise everyday, and drink plenty of water – and leave BMI in the bin.